Procedure for igniting a turbine engine combustion chamber

Abstract

A procedure for igniting a combustion chamber of a turbine engine, the chamber being fed with fuel by injectors and including an igniter mechanism igniting the fuel injected into the chamber. The procedure includes an initial stage during which fuel is injected into the chamber at a constant rate while simultaneously exciting the igniter mechanism, and in event of non-ignition of the chamber at an end of the initial stage, a second stage during which a rate at which fuel is injected is increased rapidly by 20% to 30%.

The invention claimed is: 
     
       1. A method for igniting a combustion chamber of a turbine engine, the method comprising:
 a first initial stage during which fuel is injected into the combustion chamber at a constant rate while simultaneously exciting an igniter which ignites the fuel injected into the combustion chamber; 
 a second stage during which a rate at which fuel is injected is increased rapidly by 20% to 30%; and 
 the second stage being followed by a third stage of progressively increasing the fuel flow rate by an amount that is smaller and slower than in the second stage. 
 
     
     
       2. A method according to  claim 1 , wherein the first initial stage has a duration of about 5 to 8 seconds, and the second stage corresponds to an increase in the fuel flow rate that takes place over a time of about 1 to 2 seconds. 
     
     
       3. A method according to  claim 1 , wherein the third stage corresponds to an increase in the fuel flow rate that lasts for about 10 to 15 seconds. 
     
     
       4. A method according to  claim 3 , wherein the fuel flow rate from the injectors at an end of third stage is greater than about 50% to 80% of the constant flow rate during the first initial stage. 
     
     
       5. A method according to  claim 1 , wherein a speed of rotation of the turbine engine increases progressively during the three stages. 
     
     
       6. A method according to  claim 1 , wherein all of the injectors are identical and fed with fuel in a same manner during the three stages. 
     
     
       7. A method according to  claim 4 , wherein the fuel flow rate is increased up to a maximum value in a range 1.5 times to 1.8 times the fuel flow rate of the initial stage, and the fuel flow rate is then stabilized at this maximum value until an end of the ignition procedure. 
     
     
       8. A method according to  claim 1 , wherein the combustion chamber is fed with fuel by injectors. 
     
     
       9. A method for igniting, at a ground level, a combustion chamber of a turbine engine including a compressor, the method comprising:
 a first stage during which running an electric starter connected to a shaft of the compressor causes the shaft to rotate, thereby causing air under pressure to penetrate into the chamber, while injecting fuel into the combustion chamber at a constant non-zero rate and simultaneously exciting an igniter trying to ignite the fuel injected into the combustion chamber; then 
 further to an event of non-ignition of the fuel in the combustion chamber at an end of said first stage, a second stage during which a rate at which fuel is injected is increased rapidly by 20% to 30% with respect to said constant non-zero rate, while exciting the igniter which ignites the fuel injected into the combustion chamber. 
 
     
     
       10. A method according to  claim 9 , wherein the second stage is followed by a third stage of progressively increasing the rate at which fuel is injected, by an amount that is smaller and slower than the fuel flow rate in the second stage. 
     
     
       11. A method according to  claim 9 , wherein, during the first stage, the electric starter is running at a substantially constant speed of rotation. 
     
     
       12. A method according to  claim 9 , wherein, during the second stage, the electric starter is running at a speed of rotation which is higher than a speed of rotation of the electric starter at the end of the first stage. 
     
     
       13. A method according to  claim 9 , wherein, during the second stage, the electric starter is running at a speed of rotation which increases. 
     
     
       14. A method according to  claim 10 , wherein, during the third stage, the electric starter is running at a speed of rotation which increases lower than a speed of rotation of the electric starter increases during the second stage.